Chapter 4: Electrons in Atoms

These flashcards cover key concepts from Chapter 4 about electrons in atoms, focusing on the properties of light, the development of atomic models, and quantum theory.

Electromagnetic Radiation

A form of energy that exhibits wavelike behavior as it travels through space.

Wavelength (\lambda)

The distance between corresponding points on adjacent waves.

Frequency (\nu)

The number of waves that pass a given point in a specific time, usually one second. Units are waves/second, 1/s, s-1, Hz.

Photoelectric Effect

The emission of electrons from a metal when light shines on the metal.

Quantum of Energy

The minimum quantity of energy that can be lost or gained by an atom.

Photon

A particle of electromagnetic radiation having zero mass and carrying a quantum of energy.

Ground State

The lowest energy state of an atom.

Excited State

A state in which an atom has a higher potential energy than it has in its ground state.

Bohr Model

A model of the hydrogen atom that links the atom's electron to photon emission.

Heisenberg Uncertainty Principle

It is impossible to determine simultaneously both the position and velocity of an electron.

Schrödinger Wave Equation

An equation that treats electrons in atoms as waves, forming the foundation for quantum theory.

Orbital

A three-dimensional region around the nucleus that indicates the probable location of an electron.

Quantum Number

Numbers that specify the properties of atomic orbitals and the properties of electrons in orbitals.

Aufbau Principle

An electron occupies the lowest-energy orbital that can receive it.

Pauli Exclusion Principle

No two electrons in the same atom can have the same set of four quantum numbers.

Hund's Rule

Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron.

What is the relationship between wavelength, frequency, and the speed of light?

The speed of light (c) is equal to the product of wavelength ($\lambda$) and frequency ($\nu$), expressed as c = \lambda \nu.

What is Planck's equation and what does it relate?

Planck's equation, E = h\nu, relates the energy (E) of a quantum of light to its frequency ($\nu$), where h is Planck's constant (6.626 \times 10^{-34} J \cdot s).

What are the four types of quantum numbers that specify the properties of atomic orbitals and electrons?

The four types of quantum numbers are:

• Principal Quantum Number (n): Indicates the main energy level and orbital size.
• Angular Momentum (Azimuthal) Quantum Number (l): Describes the shape of the orbital.
• Magnetic Quantum Number (m_l): Specifies the orientation of an orbital in space.
• Spin Quantum Number (m_s): Indicates the intrinsic angular momentum of an electron, or its spin state.

Atomic Emission Spectrum

The spectrum of frequencies of electromagnetic radiation emitted by an atom's electrons when they transition from a higher energy state to a lower energy state.

De Broglie Wavelength

The wavelength ($\lambda$) associated with a moving particle, given by the de Broglie equation: \lambda = h/(mv), where h is Planck's constant, m is the mass of the particle, and v is its velocity.

Electron Configuration

The distribution of electrons of an atom or molecule in atomic or molecular orbitals, following the rules of Aufbau principle, Pauli exclusion principle, and Hund's rule.

Shapes of s, p, and d orbitals

Atomic orbitals have distinct shapes:

• s orbitals: Spherical.
• p orbitals: Dumbbell-shaped, oriented along the x, y, and z axes.
• d orbitals: More complex shapes, typically cloverleaf-shaped, with various orientations in space.

Noble Gases

A group of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low chemical reactivity. They are located in Group 18 of the periodic table.

Stability of Noble Gases

Noble gases are exceptionally stable due to their full outer electron shells (valence shells), possessing a complete octet of electrons (except helium, which has a full duet). This electron configuration makes them unreactive.

What is the relationship between wavelength, frequency, and the speed of light?

The speed of light (c) is equal to the product of wavelength ($\lambda$) and frequency ($\nu$), expressed as c = \lambda \nu.

What is Planck's equation and what does it relate?

Planck's equation, E = h\nu, relates the energy (E) of a quantum of light to its frequency ($\nu$), where h is Planck's constant (6.626 \times 10^{-34} J \cdot s).

What are the four types of quantum numbers that specify the properties of atomic orbitals and electrons?

The four types of quantum numbers are:

• Principal Quantum Number (n): Indicates the main energy level and orbital size.
• Angular Momentum (Azimuthal) Quantum Number (l): Describes the shape of the orbital.
• Magnetic Quantum Number (m_l): Specifies the orientation of an orbital in space.
• Spin Quantum Number (m_s): Indicates the intrinsic angular momentum of an electron, or its spin state.

Atomic Emission Spectrum

The spectrum of frequencies of electromagnetic radiation emitted by an atom's electrons when they transition from a higher energy state to a lower energy state.

De Broglie Wavelength

The wavelength ($\lambda$) associated with a moving particle, given by the de Broglie equation: \lambda = h/(mv), where h is Planck's constant, m is the mass of the particle, and v is its velocity.

Electron Configuration

The distribution of electrons of an atom or molecule in atomic or molecular orbitals, following the rules of Aufbau principle, Pauli exclusion principle, and Hund's rule.

Shapes of s, p, and d orbitals

Atomic orbitals have distinct shapes:

• s orbitals: Spherical.
• p orbitals: Dumbbell-shaped, oriented along the x, y, and z axes.
• d orbitals: More complex shapes, typically cloverleaf-shaped, with various orientations in space.

Noble Gases

A group of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low chemical reactivity. They are located in Group 18 of the periodic table.

Stability of Noble Gases

Noble gases are exceptionally stable due to their full outer electron shells (valence shells), possessing a complete octet of electrons (except helium, which has a full duet). This electron configuration makes them unreactive.